When mankind eventually makes it to Mars, it’s going to be a momentous achievement, but the travelers who first set foot on the Red Planet probably won’t be there to stay. Eventually, however, NASA and other scientific groups around the world expect that we’ll colonize not only Mars, but other planets as well, and to realize that dream, we’re going to need places for interplanetary travelers to live.

With that in mind, NASA launched its 3D-Printed Habitat Challenge which tasked teams of researchers and engineers with designing homes for space travelers that could be created on-demand using 3D printing hardware brought along on a theoretical trip to Mars or another Earth-like planet. Now, one of the final stages of the competition has wrapped up, and NASA picked its three favorite virtual abodes.

The competition took place in three phases, and each phase is broken down into several specific tasks. The teams are currently in the last phase, and the virtual 3D construction job that just wrapped has yielded a trio of very unique habitats.

This portion of the challenge was worth $100,000 and was split roughly evenly across the top three entries. Things like architectural integrity, efficiency, and scalability were taken into account in scoring each entry, and the winner (at the top of this post) scored big points for the stability of the design.

Going forward, the biggest test for the teams will be a head-to-head build-off that will task them with printing small-scale version of their creations in front of an audience of scientists and science fans. That event is scheduled to take place from May 1st through May 4th in Illinois, and the prize purse sits at a whopping $800,000.

None of this guarantees that the first humans to colonize Mars will actually live in houses modeled exactly like the ones designed by the teams in this competition, but it’s a good way for NASA to explore novel habitat possibilities and potentially find engineers and designers it would like to work with when that day finally arrives.